Fabric filter bag



2,821,305 1/1958 Anderson..................... 2l0/486X 3,203,551 8/1965 Loan 210/486 Primary Examiner-John Adee Attorney-Fidler, Bradley, Patnaude & Lazo ABSTRACT: A fabric filter bag for a filter leaf used in filtering apparatus includes front and rear walls sewn together to form an opened-mouth bag. A closure device for closing the mouth of the bag comprises a longitudinally folded securing strip Inventor Rose M. Geister Berwyn, Illinois [2l] Appl. No. 725,071

April 29, 1968 [4S] Patented Nov. 24, 1970 Industrial Filter 8: Pump Mfg. Co. Cicero, Illinois a corporation of Illinois 3 Claims, 8 Drawing Figs.

United States Patent [22] Filed [73] Assignee [54] FABRIC FILTER BAG r 5f m w mwem w o m wmmm m am w Sten a h fl p i ee w m m mr n m w m a W0 W0 HnD. d ldan pflw a0 mMt t o o n n .m c o mr e affi ft h h mwmwmnm ahfww m m 0 wf h w mm i e m m nm m wm m mm nrmmns a l mmmm wfl ul m 0 Y Hw h dfl a a a EO 3 ennztd 2 3 3 2 MaW n ph n m n p h .l manna cmaoobot EEN 1 Ylbv .I i UI n 44.! o u fiwwwfiwmwtw 4 4 /94. s 8 w w M 07 0 24 l. M 2 "m 5 3 2 E 3 3 2 m N m m .m A u p mmm S m "n" SE f l u CD3 m m R S m Tm H 7 NW u m 9. l L mf. U Cum 1 5 1 5 UhF H 11.. m 2 0 6 2 555 5 i i:l.|. l

Paten te d Nov. 24, 1970 1 3,542,206

14 INVENTOR. ROSE M. GEISTER BACKGROUND OF THE INVENTION The present invention relates in general to a fabric bag for a filter leaf used in filtering'apparatus, and it more particularly relates to a novel fabric filter bag having a closure device for the mouth of the bag.

' Filter leaves of the type with which the present invention may be employed are arranged spatially within a pressurizable filter tank. Each filter leaf is connected in fluid communication to a common outlet manifold so that the liquid to be filtered is pumped into the tank against the perforate faces of the leaves and thence into the outlet manifold. Sincetlie particles to be removed from the liquid are too large to penetrate the perforate faces of the leaves, the particles are deposited on the faces of the filter leaves, and the remaining liquid passes through the faces ofthe leaves and enters the outlet manifold.

According to one successful technique for constructing the filter'leaves, each leaf comprises a frame mounted on'the outlet manifold and dressed with a porous fabric bag. In the past, the mouth of the fabric bag has been sealed by means of stainless steel or hard rubber clips. Closure devices of this type have not been entirely satisfactory for certain applications, because the rubber or steel was not compatible with the fluids to be filtered. In an attempt to overcome this difficulty, a nonmetallic closure device for the fabric bag has been employed. This particular filter bag utilizes a more expensive nonmetallic device comprising a pair of interlocking complementary strips which are known in the art as Velcro. This particular bag, however, was not entirely satisfactory, because it utilized a relatively large amount of the expensive Velcro to form the closure device for the bag. Furthermore, the fabric bag employing the Velcro closure device was relatively complex to manufacture.

I SUMMARY OF THE-INVENTION Therefore, it is the principal object of the present invention to provideanew and improved fabricfilter bag having a fast operating, nonmetallic closure device.

i Another object of the present invention is to provide a simplified method for making an improved fabric filter bag having a nonmetallic closure device.

A further object of the present invention is to provide a simply designed fabric filter 'bag which employs a relatively small amount of nonmetallic Velcro forming the closure device, and which is characterizedby simplicity of design.

Briefly, the above and further objects are realized in accordance with the present invention by providing a fabric filter bag having a nonmetallic closure device which comprises a pair of Velcro strips, one of the strips being folded over and secured to the marginal edge of the front wall along the mouth of the bag and the other Velcro strip beingsecured to the marginal edge of the rear wall along the mouth of the bag. The latter Velcro strip extends beyond the marginal edge of the rear wall to form a flap, whereby the flap may be folded over and interlocked with the folded strip for the purpose of releasably closing the bag.

BRIEF DESCRIPTION OF THE DRAWINGS The invention,-both as to its organization and method of operation, together with further objects and advantages thereof will best be understood by reference to the following detailed description taken in connection with-theaccompanv ing sheet ofdrawings, wherein:

FIG. 1 is a front elevationalview of a filter leaf dressed with a fabric filter bag according to the present invention;

FIG. 2 is an enlarged front elevational view of a portion of the upper left-hand corner of the fabric bag of FIG. 1 with the flap shown in an open position;

FIG. 3 is a cross-sectional view of FIG. 1 taken substantially along the line 3-3 thereof;

FIG. '4 is an enlarged view of the circled portion of FIG. 3 showing the closure device in a loosened condition;

FIG. 5 is a front elevational view of another filter leaf dressed with another filter bag in accordance with the present invention; and

FIGS. 6 to 8 illustrate the method of manufacturing the filter bag shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings and more particularly to FIGS. l -3 thereof, there is shown a fabric filter bag 10 in accordance with the present invention for a rectangular filter leaf 11 which includes a tubular frame 12 mounted on an outlet manifold 14 in a hermetically sealed tank (not shown). The interior of the bag 10 is connected in fluid communication to the manifold 14 by means of a connecter pipe 15 which has one of its ends attached and sealed to the bottom of the frame 12 and has its opposite end fitted into and sealed at an opening 16 in the manifold 14. A hole 17 (FIG. 3) in the tubular frame 12 alined with the connecter pipe 15 permits the liquid to flow from the interior of the bag 10 into the outlet manifold 14 via the connecter pipe 15. In use, the fluid to be filtered is pumped into the filter tank and is forced against the faces of the filter bag 10. As a result, certain materials, such as impurities which are too large to pass through the fabric material of the bag, are deposited on the faces of the bag 10, and the remaining fluidpasses through the faces into the manifold 14 via the pipe 15.

In order to dress the filter leaf frame 12, the frame is inserted into a'mouth at the top edge (as viewed in FIG. I) of the bag 10 until the connecter pipe 15 extends through a pro tective sleeve 19 at the central portion of the bottom of the bag 10 so that the pipe 15 can be connected to the outlet manifold 14. After the frame 12 is inserted into the bag, a nonmetallic closure device 20 secured along the mouth of the bag 10 releasably closes the mouth, the closure device 10 being shown in its closed position FIG. 1. The device 20 preferably comprises interlocking strips which are well known in the art as Velcro.

. bottom marginal edge of the front wall 22a at 25, and, in like manner, the top marginal edge of the rear sheet 19b (FIG. 3) is sewn to the bottom marginal edge of the rear wall 22b. As shown in FIG.-1, a seam is sewn at 26 along the left-hand side of the bag 10 and continuing along the lower left-hand bottom of the bag 10 to the left-hand marginal edge of the sleeve 19. Another seam is sewn along the lower right-hand bottom of the bag 10 at 27 extending from the right-hand marginal edge of the sleeve 19 to the fold line 24. The side marginal edges of the overlapping sheets 19a and19b are sewn together to form the sleeve 19 by a double row of stitching 29 for reinforcing purposes.

As shown in FIGS. 14, the nonmetallic Velcro closure device 20 comprises a tufted or matted securing strip 33 secured to the front wall 22a, and a complementary securing strip 35 secured to the rear wall 22b. The complementary strip 35 has a plurality of small hooks for interlocking with the matted strip 33. In order to obtain a double seal while using only a single strip of Velcro material, the strip 33 is folded in half longitudinally to fit over the top marginal edge of the front wall 22a along the mouth of the bag and is sewn to the front wall 22a at 37 along the bottom marginal edges of the matted strip 33 and also at 26 along the side'edges of the strip 33 and the walls 22a and 22b. As shown in FIG. 2, a lower half portion 35b of the prickly strip 35 overlies and is sewn at 39 to In order to close the mouth of the bag 10, the inner portion 33b of the matted strip 33 and the portion 35b of the prickly strip 35 overlying the top marginal edge of the'rear wall 22b are pressed into interlocking relationship with one another to form a first seal. Thereafter, the flap 35a of the 'strip 35 is folded over and pressed into interlocking relationship with the outer portion 33a of the matted strip 33 to form a second seal. To open the bag 10, the flap 35a is first released by jerking it away from the matted strip 33, and then the inner portion 33b of the matted strip 33 is separated from the portion 35b of the strip 35 by jerking them apart.

METHOD OF MANUFACTURE Referring now to FIGS. 6, 7 and 8, there is shown a method of manufacturing the fabric filter bag 10 in accordance with the present invention. Accordingly, the fabric filter bag 10 is made by a relatively simple operation which basically includes only three steps. In the first step of the sewing operation, as shown in FIG. 6, after sewing the top edges of the sheets 19a and 19b to the lower edge of the sheet 22 in a spaced-apart relationship at 25, the Velcro strips 33 and 35 are placed in a side-by-side relationship along and extending beyond the upper marginal edge of the sheet 22. As shown in FIG. 6, the strips 33 and 35 are disposed on opposite sides of the sheet 22, with the matted material of the strip 33 and the hooks of the strip 35 facing away from the sheet 22v Thereafter, both strips 33 and 35 are sewn to'the sheet 22 at 39 in one continuous sewing operation,

The second step in the procedure is illustrated in FIG. 7 and consists of folding the matted strip 33 over the upper marginal edge of the sheet 22 into an overlapping relationship with the top surface of the sheet 22 and then sewing the folded matted strip 33 to the sheet 22 at 37. According to the third basic step as shown in FIG. 8, in order to form the two faces 22a and 22b of the bag 10, the sheet 22 is folded over on itself along the fold line 24 which extends parallel to the shorter edge of the sheet 22 and which forms the border between the strips 33 and 35. As a result, the folded matted strip 33 is attached to the front face 22a, and the prickly strip 35 is attached to therear face 221; and faces the matted strip 33. The remaining'marginal edges of the sheet 22 are then sewn at 26 and 27. As mentioned above, the marginal edges of the sheet 22 opposite the fold line 24, as well as the lower lefthand portion of the sheet 22, are sewn together M26. The lower right-hand portion of the marginal edges of the sheet 22 are sewn together at 27. Furthermore, in order to help reinforce the mouth of the bag, the matted material 33 and the prickly material 35 may be sewn together along the right side (FIG. 8) at 37'. For the purpose of completing the sewing operation for the protective sleeve 19, the side marginal edges of the sheets 19a and 1% are sewn together at 29 to form the sleeve 19.

Referring now to FIG. 5, there is shown a fabric bag 40 which is another embodiment of the present invention. The fabric bag 40 is circular in shape for a circular filter leaf 41. The bag 40 surrounds a circular, tubular frame 42 which has an aperture (not shown) at its bottom for conveying the filtered fluid from the interior of the bag 40 to an outlet manifold 42 via a connecter pipe 44. The circular bag 40 includes a pair of circular sheets 46 (the rear sheet is not shown in the drawings) of fabric material. The sheets are sewn together along the marginal edge of the lower half of their periphery at 48. A nonmetallic Velcro closure device 50 extends along the marginal edge of the upper half of the periphery of the sheets 46 to releasably close the bag 40 in the same manner as the above-described closure device 20. A protective sleeve 52 is sewn to the lower portion of the walls 46 to surround the connecter pipe 42 in the same manner as the above described sleeve 19.

In view of the foregoing description, it should now be apparent that there is provided in accordance with the present invention an economically constructed fabric filter bag and a method for making it. The inventive filter bag comprises a front wall of fabric material and a rear wall of fabric material sewn together along their marginal edges to form an openedmouth bag for receiving a filter leaf frame. A nonmetallic fastening or closure device is secured along the marginal edges of the front and rear walls at the mouth of the bag for the purpose of releasably closing the bag and provides a double seal when closed. The nonmetallic closure device comprises two separate interlocking securing strips, One of the strips is folded longitudinally to fit over the marginal edge of the front wall along the mouth of the bag. The other strip is sewn to the inner face of the rear wall at its marginal edge to interlock with the other securing device. A portion of the latter strip extends beyond the rear wall .to form a flap. In order to releasably close the bag, the inner portion of the first strip is pressed into interlocking engagement with the portion of the second securing strip overlying the rear wall to form a first seal, and the flap portion of the second securing strip is folded over and pressed into interlocking relationship with the outer portion of the first securing strip to form a second seal.

While the present invention has been described in connection with particular embodiments thereof, it will be understood that many changes and modifications of this invention may be made by those skilled in the art without departing from the true spirit and the scope thereof. Accordingly, the appended claims are intended to cover all such changes and modifications as fall within the true spirit and scope of the present invention.

lclaim:

1.. A fabric filter bag for a filter leaf, wherein the improvement comprises:

a front porous wall and a rear porous wall connected together along a portion of their marginal edges to form an opened-mouth bag for receiving the filter leaf;

a first securing member connected to a marginal edge of said front wall along the mouth of said bag, said first member having an outer portion extending along the outside surface of said frontwall and havingan inner portion extending along the'inside surface of said front wall, said first securing member having a plurality of securing elements on the surface thereof; and

a second securing member connected to an inside marginal edge of said rear wall along said mouth of said bag and extending beyond said marginal edge of said rear wall to form a flap, said flap being folded over said marginal edge having said first securing member, said second securing member having a plurality of securing elements on its surface for releasably interlocking with the securing elements of said first securing member, the securing elements of one of the securing members comprising a plurality of hooklike members and the securing elements of the other securing member comprising a tufted material, whereby the portion of said second securing member overlying said rearwall interlocks with said inner portion of said first securing member and said flap portion of said second member interlocks with said outer portion of said first securing member 4.

2. A filter bag according to claim 1, wherein the width of said inner portion of said first securing member extending along the inside surface of said front wall is substantially equal to the width of the portion of said second securing member connected to the inside of said rear wall.

3. A filter bag acqordingto claim 2, wherein said flap of said second securing member is adapted to fold over said first securing member along said mouth of said bag to interlock with said outer portion of said first securing member. 

